Coil spring mattress construction

ABSTRACT

A more versatile pocket coil mattress provides increased support in the perimeter side regions of the mattress in combination with increased support in the main sleeping area. The shape, preloading and characteristics of the pocket coil springs has changed to decrease compression per unit of force applied while still maintaining the desired user response of a pocket coiled mattress.

FIELD OF THE INVENTION

The present invention is directed to pocket coil mattresses and inparticular to improvements with respect to a perimeter support regionand a main sleep area of the mattress.

BACKGROUND OF THE INVENTION

Pocket coil mattresses are known for having extremely appealing flexproperties and the ability to resiliently conform to different usersthereby providing a better night's sleep. These mattresses haveindividual coil springs maintained in a compressed state in their ownfabric pocket. Typically the fabric pockets are sewn in long strips andsecured to form the mattress core.

Many pocket coil mattresses include either an edge wire around themattress that connects to edge coil springs and provides additionalstiffness for seating at the edge of the mattress or; a hard compressionfoam encasement to replace the edgewire, as well as between 25% and 33%of the spring core itself to prove a strengthened seating edge. The edgewire although helpful in providing this additional support, is notdesirable in that the mattress can be permanently damaged if subjectedto significant bending. Bending of a mattress is often necessary toallow passage of the mattress through a restricted access such as anarrow staircase or other restriction. Furthermore bending of themattress is desirable for adjustable position leisure beds or hospitaltype beds. In the case of a foam encased seating edge, the end resultdoes allow bending and does not have the sustainable performance andlong term recovery level as an complete spring edge with the attachededgewire. A foam encasement seating edge is not a design that isapplicable to the present invention of pocket coil spring core assembly.

In our earlier U.S. Pat. No. 6,295,676, a pocket coil mattress isdisclosed that does not include an edge wire. This mattress allowsbending of the mattress, however the edge of the mattress issubstantially compressed when a user sits on the edge of the mattress.The ability to provide firm edge support and desirable flex for sleepingis challenging.

The present invention provides an improved pocket coil mattress thatallows for the bending thereof while providing substantially improvededge support and without impacting on the uniform comfort of the balanceof the mattress spring underlying its sleep surface when fully finishedwith upholstery padding material. These advantages are realized whilestill providing a main sleep area and perimeter support region that hasthe comfort advantages that is now expected with a pocket coil mattress.

SUMMARY OF THE INVENTION

A mattress according to the present invention, comprises a main sleeparea surrounded by a perimeter support region. The main sleep area andthe perimeter support region are defined by wire coil springs containedwithin individual fabric pockets. The wire coil springs in the mainsleep area are arranged in a honeycomb offset series of rows. The wirecoil springs in the perimeter support region are of a different wireconstruction and have different flex characteristics from the wire coilsprings in the main sleep area. The wire coil springs in the perimetersupport region are arranged in side by side rows and thus define anon-honeycomb arrangement. The perimeter support region has at least twoside by side rows about the mattress. The perimeter support regionincludes four corner configurations that each have at least eight crossconnected wire coil springs. These coil springs are cross connected tojoin coil springs of the same row and opposite rows. Between the cornerconfigurations wire coil springs of the perimeter region are onlyconnected across rows. The mattress is made without an edge wire aboutthe perimeter of the mattress. The coil springs of the perimeter regioncooperate to accommodate substantial resilient bending of the mattressin a length thereof while providing improved support for side seating.

According to an aspect of the invention, the wire coil springs of theperimeter support region are of a smaller coil diameter relative to thediameter of the wire coil springs of the main sleep area.

According to a further aspect of the invention, the wire coil springs ofthe perimeter region have a gauge of about 14.5.

In a further aspect of the invention, the wire coil springs of the mainsleep area are of a gauge of about 15.5.

According to a preferred aspect of the invention, the wire coil springsof the perimeter support region are of a diameter of about 2 inches atthe ends thereof and the springs taper inwardly to a narrow waist ofabout 50 millimeters.

In a further aspect of the invention, the perimeter support regionincludes at least three rows of wire coil springs of a gauge between 14and 15.

In yet a further aspect of the invention, the perimeter support regionat the top surface thereof, is connected by a flexible high-strengthplastic mesh extending over the mattress. Preferably the bottom surfaceof the mattress is also connected a flexible high strength plastic mesh.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are shown in the drawingswherein:

FIG. 1 is a perspective view of the new mattress showing resilientdeformation of a corner region of the mattress;

FIG. 2 is a perspective view of the mattress showing bending of themattress to accommodate variable position beds;

FIG. 3 is a perspective view of the mattress showing bending thereofabout a midpoint of the mattress;

FIG. 4 is a partial perspective view of the corner configuration of themattress;

FIG. 5 is a top view showing a number of individual components themattress;

FIG. 6 is a partial top you showing the wire coil springs of theperimeter region and the wire coil springs of the main sleep area;

FIG. 7 is a partial perspective view of coil springs preloaded andmaintained in their own individual fabric pocket:

FIG. 8 is a partial top view of the twin mattress having two rows ofwire coil springs defining the perimeter support region;

FIG. 9 is a partial perspective view of a prior art mattress showingresilient deformation of the edge of the mattress when a person sitsthereon;

FIG. 10 shows the improved perimeter support region of the presentinvention with a person sitting thereon;

FIG. 11 is a partial perspective view showing details of the perimetersupport region and main sleep area;

FIG. 12 is a partial perspective view similar to FIG. 11 showing ourprior art arrangement;

FIG. 13 is a perspective view of the new coil spring used in theperimeter support region;

FIG. 14 is a side view of the new coil spring of FIG. 11 showing thenarrow waist;

FIG. 15 is a side view of the coil spring used in the main sleep regionillustrating the barrel shape profile thereof;

FIG. 16 is a side view of the coil spring used in the main sleep area inan initial uncompressed state and transitioning to the preloaded statemaintained in the fabric pocket as shown on the right-hand side;

FIG. 17 is a side view showing the different preloaded compressed statesof the coil springs of the perimeter support region and the main sleeparea;

FIG. 17a is a sectional view showing the gauge of the wire coil springof the perimeter support region;

FIG. 17b is a sectional view showing the gauge of the wire coil springof the main sleep area;

FIG. 18 is a side view showing the spring of the border region relativeto the main sleep area

FIG. 19 is a partial perspective view of a corner configuration of themattress with the fabric cover mattress secured above; and

FIGS. 20 and 21 are partial side views of same coil spring shownenclosed into different types of fabric pocket.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 through 3 in the application, illustrate various bentconfigurations of the mattress that commonly occur. In FIG. 1, one ofthe corners of the mattress has been bent upwardly. In FIG. 2, one endof the mattress has been raised as may be necessary for hospital beds orvariable leisure beds that are moveable to a sitting configuration. Thistype of bending of the mattress intermediate its length, is now a commonrequirement. The bending of the mattress into the ‘U’ configuration ofFIG. 3, may be necessary to move the mattress through a restricted spacesuch as a narrow stairwell. In recent years, larger mattresses are morepopular and access to the bedroom may be limited or restricted. Having apocket coil mattress without a perimeter edge wire, provides thisflexibility and easily accommodates varying the components of themattress that may be required for different models.

Our earlier U.S. Pat. No. 6,295,676 discloses a pocket coil mattressthat does not include an edge wire and as such the mattress can bendintermediate its length. Although this structure has many advantagesover existing mattresses, it has some disadvantages with respect to edgeseat support. In pocket coil mattresses, the ability of the mattress toindependently respond to the movement of two users and allow forsignificant isolation of these movements, is a primary advantage. Theperimeter support region of the mattress includes two or more rows ofcoil springs that have different flex characteristics relative to thecoil springs of the interior main sleep area. The border springsintermediate the corners, although stiffer than the coil spring of themain sleep area, still deform significantly and seating support on anedge mattress causes unwanted sidewall distortion as shown in the priorart mattress of FIG. 9. The present invention provides a structure,where these disadvantages are overcome.

The mattress 2 as shown in FIG. 4, includes a mattress core 6 having aperimeter support region 10 about the main sleep area 50 of themattress. The perimeter region 10 includes an outer row 12 of pocketcoil springs, a middle row 14 of pocket coil springs and in the mattressof FIG. 4, an inner row 16 of pocket coil springs. The main sleep area50 has the coil springs thereof arranged in a honeycomb pattern. Pocketcoil springs of the main sleep area are of a lighter gauge wire and aremore compressible than coil springs of the perimeter support region 10.

The perimeter support region 10 includes four corner configurations 30and in the case of a queen or king mattress, each corner configurationis defined by 15 connected pocket coil springs. Each of these pocketcoil springs are mechanically connected to adjacent pocket coil springsas indicated by the mechanical connectors 32. These mechanicalconnections are preferably upholstery stables located at the point ofcontact between adjacent pocket coil springs. With this arrangement alinked series of pocket coil springs is provided in each corner of themattress. These connected coil springs are in contrast to the coilsprings of the main sleep area that are independent. The mattress 2,with the four corner configurations 30, provide a more rigidconfiguration supporting the coil springs of the perimeter supportregion 10 between corner configurations.

The coil springs, between two corner configurations of the perimetersupport region, are merely connected to adjacent pocket coil springs ofthe respective row or rows. As can be appreciated these connected coilspring do not move independently due to the common mechanical connection32 but have more independent movement than the coil springs of thecorner configurations.

The corner configuration 30, as shown in FIG. 4, provides an integratedsupport structure at each corner of the mattress that act to stabilizeother pocket coil springs of the perimeter support region 10 as well asthe coil springs of the main sleep area 50. The stable cornerconfigurations 30 and the individual coils of the mattress 2 areconnected by an upper high strength reinforcing mesh 60 and a lower highstrength reinforcing mesh 62. Preferably, the mesh 60 and 62 is areinforced, extruded fiber mesh. The mesh may be natural sourced ormanmade. The mesh cooperates with the related components. High strengthplastic mesh can also work. In addition to the various mechanicalconnections of the coils to each other shown at the upper surface or topof the coils springs, the coil springs are also preferably connected ina similar manner on the lower surface of the mattress. These connectionspass through the fabric pockets 36.

FIG. 5 shows a queen-size mattress having the perimeter support region10 surrounding the main sleep area 50. The spring coils of the mainsleep area 50, laid out in a honeycomb configuration in contrast to thespring coils of the perimeter support region 10 that are positioned in aside by side configuration. Only a portion of the upper plastic gridmesh 60 is shown in the lower left corner of FIG. 5, and locates thecorner configuration shown in greater detail in FIG. 6. For betterunderstanding, the fabric pockets 36 of the coil springs are onlypartially shown.

The corner configuration 30 of FIG. 6 (corresponding to a queen or kingsize mattress) includes the first four coil springs in each of the threerows of coil springs in both the length and the width of the mattressand are mechanically secured. The mechanical fasteners 32 connect t eachcoil spring to its abutting adjacent coil springs. Some of the coilsprings include four mechanical connection points. The cornerconfiguration 30 includes the first four coil springs in each of therows of the perimeter support region 10 in both the length and widthdirection. The coil springs of the perimeter region 10 located betweencorner configurations, only include mechanical connections 32 that jointhe coil springs in adjacent rows not along a row. The top and bottomhigh strength plastic mesh 60 and 62 connect the spring coils of theperimeter support region as well as the spring coils of the main sleeparea 50.

These corner configurations in combination with the high strength mesh,anchor and secure the remaining coil springs of the perimeter supportregion between the corner configurations. Each of the wire coil springsof the perimeter support region, is of a reduced overall diameterrelative to the diameter of the wire coil springs of the main sleep area50. Furthermore, the coil springs in the main sleep area 50, are in thehoneycomb configuration and provide independent movement while alsosupporting each other as the coil springs are closely packed.

FIG. 7 shows an example of wire coil springs located within theirconnected fabric pockets 36. The pockets are of a fixed length andmaintain the wire coil springs in a partially compressed or preloadedstate.

FIG. 8 shows part of a twin size mattress with a reduced perimetersupport region 10 having only two rows of wire coil springs surroundingthe main sleep area 50. In this case the first three coil springs of thecorner configuration 30 in each direction, are mechanically connected byfasteners 32.

One of the problems associated with pocketed coil spring designmattresses, is that a person sitting on a side portion of a prior artmattress, as shown in FIG. 9, creates significant compression anddistortion of the side wall 42 of the mattress as indicated by outwarddistortion of the sidewall of the mattress and distortion ripples 54.

A mattress with the new corner configuration having the improved coilwire springs in the perimeter support region, undergoes less compressionand less sidewall outward distortion and therefore fewer distortionripples occur as the perimeter support region is stiffer. With thisimprovement there is still some distortion of the side wall of themattress as evident at 56, however the distortion is limited andimproved seat support is provided. Furthermore although the perimetersupport region has been stiffened, the desirable sleeping comfort of themattress is maintained.

FIGS. 11 and 12 provide a comparison of new pocket coil spring mattressshown in FIG. 11 and the prior art pocket coil spring mattress as shownin FIG. 12. For a better understanding, the filler springs 28 are shownin an uncompressed state and are of a length of 10 inches indicated at53. The end diameter indicated by 57 is 2 inches. The spring is barrelshaped with a waist of 55 mm. In contrast the uncompressed state of theprior art filler spring 28 a is 9.5 inches indicated at 55, the enddiameter 59 is 2.25 inches and the waist of the barrel shape is 58 mm.

Improvements with respect to the flex and shape of the wire coil springsand the relationship of the wire coil springs of the perimeter supportregion to the coil springs of the main area 50, can be appreciated froma review of FIGS. 13 through 15. The heavier gauge wire of the coilsprings in the perimeter support region has a tensile strength in therange 240,000 to 280,000 psi whereas the wire of the lighter gauge coilsprings of the main sleep area has a tensile strength in the range of290,000 to 310,000 psi.

Wire coil spring 24 of the perimeter region, is preferably of a gauge of14.5. The height of the spring before compression is approximately 10 to10.5 inches and the spring end diameter is 2⅛ inches. The number ofturns of the spring is six. As shown in FIG. 14, the spring is formed totaper inwardly to a reduced waist having a diameter of approximately 50mm in the preferred embodiment. The perimeter support springs arecompressed from the uncompressed state and received in a pocket thataccommodates a spring length of about 6½ inches. Our prior art springused at the sides of the mattress, has a barrel type shape that tends todistort outwardly when compressed. In addition, the uncompressed stateof the spring was 9 to 9.5 inches. The tapered waist of the new springreduces outward distortion during substantial compression that mayoccurs when a person sits on the side edge of the mattress and also hashigher support load due to the increased compression due to its longeruncompressed length. The load lift capability of the spring has beenincreased without changing the overall length, gauge or strength of thewire. In this way, the load lift capability has been increased whilestill maintaining uniform comfort balance across the finished mattress.

The new mattress with the perimeter support region of the revised shapeand stronger coil springs, provides improved seat support between theanchoring corners. The improved load carrying capabilities of eachspring is provided by reducing the diameter of the spring and changingthe shape of the spring from a barrel shape to a tapered waist design.The length of the perimeter support region springs has been increased(preferably from 9.5 inches to 10.5) and the preload of each spring hasincreased and is in the range of 900 to 1000 grams whereas the prior artcoil spring typically had a preload in the range of 750 to 780 grams.The diameter of the prior art spring was about 2.5 inches and the centerwaist diameter was 57 mm. The wire length of about 47 inches wasmaintained. Therefore the wire coil spring 24 has been redesigned toprovide additional support in a side region of the mattress that isprone to user distortion due to a concentrated load created by sittingon a side or end of the mattress. The enhanced load carryingcapabilities of the modified spring and the stiffer cornerconfigurations cooperate and reduce sidewall distortion whilemaintaining independent sleep support in the main sleep area of themattress as well as compatible sleep support in the perimeter supportregion. Also side seating on the mattress is improved as there is lesscompression.

The filler springs in the sleep central area preferably are also beenmodified to increase the length of the uncompressed spring to about 10inches whereas our prior filler spring was of a length of 9 to 9.5inches. The diameter of the spring is now preferably 2 inches whereaspreviously it was about 2.25 inches. The waist of its barrel shape isnow 55 mm compared to the previous 58 mm. Both the new and old springsare 6 turn springs of the same 15.5 gauge that are pre-compressed andmaintained in a 6.5 inch pocket. The preload of the filler spring hasincreased to 490 to 500 grams compared to the previous preload of about430 grams. The changes to the filler spring cooperate with the newperimeter support region spring to provide an effective transition atthe junction of the sleep central area and the perimeter support region.

Diameters of both edge (border) coil and sleep central area (filler)coil, despite the difference in wire gauge are close in size so as notto distort the final assembled core in terms of resilient performanceand responsive compliance across the core surface that translates aboveand below in the finished mattress. This describes desirable, uniformperformance and compliance across the finished (upholstered and covered)mattress from side to side and head to foot. The springs cooperate toprovide a proportional balance between the perimeter edge and the sleepcentral subassemblies placed in the final pocket spring core assembly.

Surprisingly, the additional pre-compression and changes to theperimeter coil springs, support the load of a person sitting on the sideof the mattress with less compression of the mattress sidewall. Thesechanges in combination with the increased load carrying capability ofthe main sleep area springs per unit of compression, provides a pocketcoil mattress with the known desired sensation of pressure relief, greatsupport and fast response to the user's movement. The modified perimeterand main sleep area springs have greater load carrying capability perunit of compression while still providing the desired response andwithout a load ridge at the junction of the perimeter support springsand the main sleep area springs. Both types of springs have a higherrate of recovery without impacting the user's perception of greatsupport and appropriate response to user movement.

The extent of side edge compression of the mattress due to a usersitting thereon, has substantially decreased from 3 to 4 inches forexample to preferably 1 to 2.5 inches. This change provides theadditional support and allows the mattress able to meet the need ofvarious bed applications without using a border edge wire. Furthermorethe springs are less likely to fatigue over the life of the mattress dueto the higher strength.

FIG. 16 illustrates one of the filler springs 28 undergoing compressionand being retained in the fabric pocket 36 in a compressed state topreload the spring. The individual fabric pockets 36 are of theappropriate size to maintain the desired initial compression of thesprings. Although the fabric pocket is shown with spring 28 a similarpocket arrangement is used to maintain the initial compression ofperimeter springs 26.

FIG. 17 shows the assembled core of the mattress 2 together with top andbottom upholstery type cushioning material 93 that may vary betweendifferent mattress models. A fabric outer material would be present tofinish the mattress. Other intermediary layers may also be present asfound in existing pocket coil mattresses.

FIG. 18 shows some movement of the coil spring when a weight is appliedto the edge of the mattress. FIG. 19 shows additional layers of themattress 2 supported by the pocketed coil spring core 6. These variouslayers are preferably secured by tufting.

FIGS. 20 and 21 show the wire coil springs 28 received in pockets ofdifferent types of material 36 a and 36 b. The material of the pocketmay vary depending upon the particular characteristics of the mattress.Some pocket material is thicker (pocket material 36 b) than other pocketmaterial (pocket material 36 a) as exemplified in these figures.Somewhat surprisingly the number of coils provided in the length orwidth of the mattress may vary depending upon a change in the thicknessof the pocket material.

The applicant has found, that improvements to pocket coil mattresses canbe realized by providing additional support created by the connectedcorner configurations. Further improvements in the characteristics ofthe side edge of the mattress can be realized by changing the shape andload carrying capacity of the wire coil springs used in the perimetersupport region. Further improvements can be realized by utilizing wirecoil springs in the main sleep region that are of reduced diameter andof greater load carrying capabilities relative to the prior artmattresses.

Although the invention has been described herein in detail appreciatedthe variations may be made thereto without departing from the attachedclaims. The detailed description has focused on applicant's preferredembodiments however the attached claims define the applicant'sinvention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A mattress comprising amain sleep area surrounded by perimeter support region with both themain sleep area and the perimeter support region being defined by wirecoil springs contained within fabric pockets; the wire coil springs inthe main sleep area are arranged in honeycomb offset rows; the wire coilsprings in the perimeter support region are of a different wireconstruction having different flex characteristics relative to the wirecoil springs in the main sleep area; said wire coil springs in saidperimeter support region are arranged to define at least two side byside rows about the mattress; and wherein said wire coil springs of saidperimeter support region define four corner regions of the mattress witheach corner region including at least 8 wire coil springs crossconnected and joining adjacent wire coil springs of the respective rowand adjacent wire coil springs of opposite rows; said wire coil springsof the perimeter region cooperating to allow said wire coil springsbetween said corner regions to accommodate substantial resilient bendingof said mattress in a length thereof.
 2. A mattress as claimed in claim1 wherein said wire coil springs of said perimeter region are of asmaller spring coil diameter relative to the diameter of the wire coilsprings of said main sleep area.
 3. A mattress as claimed in claim 2wherein said wire coil springs of said perimeter region have a gauge ofabout 14.5.
 4. A mattress as claimed in claim 3 wherein said wire coilsprings of said main sleep area have a gauge of about 15.5.
 5. Amattress as claimed in claim 3 wherein said wire coil springs of saidperimeter region are of a diameter of about 2 inches at the ends thereofand taper inwardly to a narrow waist of about 50 mm.
 6. A mattress asclaimed in claim 2 wherein said perimeter support region includes atleast 3 rows of wire coil springs and said wire coil springs are of agauge of between 14 and
 15. 7. A mattress as claimed in claim 6 whereinsaid wire coil springs of said perimeter region are connected at bothends of said coil springs.
 8. A mattress as claimed in claim 7 whereinsaid perimeter support region on a top surface and a bottom surface isconnected by a flexible high strength mesh.
 9. A mattress as claimed inclaim 1 wherein the wire coil springs in said perimeter support regionhave a preload force of at least 970 grams.
 10. A mattress as claimed inclaim 9 wherein the wire coil springs in said main sleep area have apreload force of at least 490 grams.
 11. A mattress as claimed in claim10 wherein the wire coil springs in said perimeter support region have apreload force in the range of 970 to 1000 grams.
 12. A mattress asclaimed in claim 11 wherein the wire coil springs in said main sleeparea have a preload force in the range of 490 to 520 grams.